Poor quality scanning - PhotoSmart Prem c310a

[pete_777]

Running hplip version 3.22.2 on Kubuntu 21.10

From https://developers.hp.com/hp-linux-imaging-and-printing/supported_devices/index

Model Name: HP PhotoSmart Prem c310 Series
Min. HPLIP version: 3.10.9
Chrome OS Support: Yes
Driver Plug-in8: No
Support Level9: Full
Print Mode: Color
Scan to PC3: Yes
PC Send Fax5: No
Connectivity, USB, Network, Par: USB

Any attempts at scanning are producing results that are far from clear. I have changed DPI up to 600, used various scanning tools like Document Scanner, gscan2pdf, XSane and Scanlite, yet all to no avail.

There were some errors in the installation ( see [content removed] ) but I assume they were simply KWallet only, and not hplip as such.

Even when I use a completely clear original with very sharp and clear wording, the results from scanning and fuzzy, hazy. Like a blue/grep impression over the scanned document. Have cleaned the glass on the printer/scanner; no difference in scanned quality. Ran the diagnostics, there was a few warnings for the same file, not being able to access /etc/cups/ppd/Photosmart-Prem-C310-series.ppd

That file is present ..

ls -al /etc/cups/ppd/Photosmart-Prem-C310-series.ppd
-rw-r----- 1 root lp 30531 Jun 2 08:59 /etc/cups/ppd/Photosmart-Prem-C310-series.ppd

root is the owner, group of "lp" can view - not sure if the scanning runs under group "lp" ? If I do an "id", I'm not in group "lp", yet am in "lpadmin". But surely if the scanning problem was permission based, the scanning may not work at all ??

Any ideas please ?

[pete_777]

Is it even possible to obtain "OCR quality" scanning on Linux/Kubuntu ?